1. Field of the Invention
The present invention relates to an image processing apparatus and, in particular, to a process for combining a plurality of image layers to display a combined image.
2. Description of the Related Art
Video input and output apparatuses using a graphical user interface (GUI) have been known. Such apparatuses have a first image layer that displays a GUI and a second image layer that displays video pictures. Users can intuitively carry out image processing on the second image layer by operating the apparatus while viewing the display of the combined first and second image layers (for example, while viewing the GUI on the first image layer).
On the other hand, users generally have a requirement for changing a partial image of the displayed image by a user operation. For example, Japanese Patent Laid-Open No. 2001-28063 discloses a technology in which a user transforms a partial image in a predetermined target image area by operating an external switch.
However, in the technology in which a user executes an operation to transform a partial image in a predetermined target area on a second image layer, which is the target image to be processed, in Japanese Patent Laid-Open No. 2001-28063, if a GUI and the second image layer, which is a target image to be processed, are combined and a user operates the GUI in place of a switch, the display of the second image layer cannot be changed in response to a change in the display of the GUI, which is a problem.
For example, when a user processes a partial image on the second image layer by operating a GUI, the consistency between a processed position and shape of the image on the second image layer and the position and shape of the GUI on the first image layer must be maintained. Accordingly, when changing the position and shape of a graphic element of the GUI, a predetermined area of an image to be processed requires re-setting. However, it is difficult to determine the precise position and shape of the graphic element of the GUI displayed on the first image layer from the second image layer, where a background image is displayed. Also, in the case of apparatuses for recording and playing back a moving image, it is difficult to set the area of an image to be processed, since the image displayed on the second image layer is always changing.